Stabilizing high speed railway trucks

ABSTRACT

A railway vehicle has a bolster interposed between the truck and the car body, the bolster comprising upper and lower parts. The upper bolster part mounts the vehicle body for vertical springing movement only; an articulated linkage alternatively connects the two bolster parts or the truck frame and the lower bolster part for lateral arcuate movement about a longitudinal tilting axis under the action of motors; means permitting pivoting of the body on the truck is provided alternatively respectively between the truck frame and the lower bolster part or between the two bolster members. When the pivoting is between the truck frame and the bolster the truck pivot is maintained automatically centered by motor means opposing the centrifugal forces. In a complete system wherein the vehicle body is tilted automatically detectors measure the curvature of the track and the tilting of the truck and control the tilting of the vehicle body.

United States Patent Dobson et al.

154] STABILIZING HIGH SPEED RAILWAY TRUCKS [72] Inventors: Richard N. Dobson, Burlington, On-

tario; Kenneth E. Boyce, Hamilton, Ontario; John A. Gaiser, Stoney Creek, Ontario; Conrad David Gris, Hamilton, Ontario, all of Canada [73] Assignee: Dominion Foundries & Steel Limited, Hamilton, Ontario, Canada 22] Filed: Jan. 14,1970

211 Appl.No.: 2,796

Related U.S. Application Data [63] Continuation-impart of Ser. No. 790,757, Jan. 13,

[52] U.S. Cl. ..105/201, 105/1'64, 105/171, 105/185,105/193, 105/197 A, 105/197 R,

[51] Int. Cl ..B61f 3/08, B61f 5/20, B61f 5/24 [58] Field ofSearch..l05/l64,167,168,190 R, 171, 105/185, 189, 190 A, 191, 193, 197 R, 197

[56] References Cited UNITED STATES PATENTS 1,954,705 4/1934 Kruckenberg et a1. ..105/168 2,474,471 6/1949 Dolan ..105/164 2,500,906 3/1950 Soloview ..105/190 R 2,520,944 9/1950 Lynn et al ..105/164 X [451 Dec. 5, 1972 2,568,401 Lynn et a1 ..105/171 X 2,633,811 4/1953 Poage ..105/197 B 3,376,831 4/1968 Eaton et al.... ..105/199 R 3,403,638 10/1968 Hirst ..105/199 R 3,417,711 12/1968 L'ich ..105/199 R X 3,433,177 3/1969 Cripe ..105/199 R 1,522,726 l/l925 Knape ..105/168 2,309,265 l/l943 Traville, Jr. et al ..105/19OR Primary Examiner-Arthur L. La Point Assistant Examiner-Howard Beltran Attorney-Church and Rogers [5 7 ABSTRACT A railway vehicle has a bolster interposed between the truck and the car body, the bolster comprising upper and lower parts. The upper bolster part mounts the vehicle body for vertical springing movement only; an articulated linkage alternatively connects the two bolster parts or the truck frame and the lower bolster part for lateral arcuate movement about a longitudinal tilting axis under the action of motors; means permitting pivoting of the body on the truck is provided alternatively respectively between the truck frame and the lower bolster part or between the two bolster members. When the pivoting is between the truck frame and the bolster the truck pivot is maintained automatically centered by motor means opposing the centrifugal forces. In a complete system wherein the vehicle body is tilted automatically detectors measure the curvature of the track and the tilting of the truck and control the tilting of the vehicle body.

20 Claims, 10 Drawing Figures PATENTED 1 2 3,704,670

SHEET 1 0F 8 0m mm mm mm a)! l N VENTORfi RICHARD N. DOBSON NNETH E. BOYCE HN A. GAISER CONRAD D. GRIS BY M PATENT AGENTS ATENTEDnEc 5 m2 3.704.670

SHEEI 2 BF 8 FIGB - INVENTORS RICHARD N. DOBSON KENNETH E. BOYCE JOHN A. GAISER CONRAD pfims BY a 09.

PATENT AGENTS PATENTED DEC 5 I972 3 7 O4 6 7 O INVENTORS RICHARD N. DOBSON KENNETH E. BOYCE JOHN A. GAISER CONRAD D. GRIS BY I PATENT AGENTS PATENTE D 5 I973 3. 704,670

sum 7 UF 8 l I I ll KENNETH E BOYCE JOHN A. GAISER CONRAD D. GRIS BY r PATENT AGENTS l N I N v I m N INVEATORS RICHARD N. DOBSON KENNETH E. BOYCE JOHN A. GAISER CONRAD D. GRIS BY {WW PATENT AGENT 1 STABILIZING HIGH SPEED RAILWAY TRUCKS I CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of our earlier application, Ser. No. 790,757, filed January 13, 1969.

FIELD OF THE INVENTION This invention is concerned with improvements in or relating to railway trucks, and especially but not exclusively to such trucks intended for use in high speed passenger cars.

REVIEW OF THE PRIOR ART It is a continuing requirement for railway vehicles, particularly passenger cars, to achieve higher speeds combined with a safe, comfortable ride, and it is now considered a normal requirement for such cars to travel at speeds as high as 120 m.p.h., speeds in excess of this figure usually requiring a specially built track structure. It is of course apparent that faster scheduled train times can be achieved if the average speed can be maintained as near as possible to the maximum, even around curves, but attempts to take present normal passenger cars around curvesat these speeds, even when the track is given the maximum possible banking elevation, results in uncomfortably high lateral forces (i.e., greater than 0.05g) being applied to the passengers. Accordingly, a number of proposals have been made hitherto to tilt the cars about a longitudinal axis, and thereby reduce the lateral force applied to passengers.

It is found that careful location of the tilting or roll axis is required relative to the center of gravity if the maximum effective banking angles are to be compatible with passenger safety. From considerations of speed, comfort and safety the center of gravity 'is designed to be as low as possible, and desirably the roll axis should be just below the center of gravity, so that relatively high tilt angles can be employed in curves, while the resultant of the centrifugal and gravity forces is still within the middle one third of the track 'gauge, which is the generally accepted safety limit.

It is desirable also to provide as far as possible that the structure and components used in the trucks are, as much as possible, the same or very closely similar to those of existing vehicles, so that the servicing and maintenance thereof can readily be accomplished with existing railway equipment, shop skills and personnel.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a new railway truck providing for tilting of the car body thereon, particularly such a truck intended for high speed passenger vehicles.

It is a more specific object to provide a new high speed railway truck providing for tilting of the car body thereon and employing relatively conventional suspension components.

It is a further specific object to provide a new high speed railway truck providing for tilting of the car body thereon under the controlof inertial devices so as to reduce or balance out to zero the lateral acceleration forces due to the vehicle traversing a curve.

In accordance with the present invention there is provided a railway truck comprising a truck frame member constituted by transversely spaced side frames and transom means extending between and connecting the said side frames; at least two wheel and axle assemblies mounted by the frame member and on which the truck 'runs; bolster means mounted by the frame member and adapted to support a vehicle body thereon for pivoting and tilting movement relative thereto, the said bolster means comprising an upper bolster member and a lower bolster member, and spring mounting means on the upper bolster member for mounting the vehicle body for generally vertical springing movement relative thereto, pivotal mounting means connecting the lower bolster member and the frame member for pivoting movement about a generally vertical pivot axis, link connecting means pivotally connected to the upper and lower bolster members and connecting the said members for lateral, arcuate movement of the upper member relative to the lower member about a longitudinal tilting axis of the frame member; and motor means connected between the link-connected members and operative to produce the said lateral, arcuate movement therebetween.

Also in accordance with the present invention there is provided a railway truck comprising a truck frame member constituted by transversely spaced side frames and transom means extending between and connecting the said side frames; at least two wheel and axle assemblies mounted by the frame member and on which the truck runs; bolster means mounted by the frame member and adapted to support a vehicle body thereon for pivoting and tilting movement relative thereto, the said bolster means comprising an upper bolster member and a lower bolster member, spring mounting means on the upper bolster member for mounting the vehicle body for generally vertical springing movement relative thereto, pivotal mounting means connecting the upper and lower bolster members for pivoting movement about a generally vertical pivot axis, and link connecting means pivotally connected to the lower bolster member and the frame member and connecting the lower bolster member for lateral, arcuate movement relative to the frame member about a longitudinal tilting axis of the frame member; and motor means connected between the link-connected members and operative upon actuation of the motor means to produce the said lateral, arcuate movement therebetween.

Preferably, the said motor means that is operative between the link-connected members is controlled by commands from suitable devices, such as an accelerometer carried by the upper bolster member, or an inertial controller, carried by the vehicle, or by the preceding vehicle, or by the locomotive drawing the vehicle. Preferably, the said motor means that are operative between the truck frame member and the frame pivot member are also under control of the said devices.

DESCRIPTION OF THE DRAWINGS Particular preferred embodiments of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, wherein '3 FIG. 1 is a perspective view of a first embodiment with thebolster thereof shown displaced vertically from the truck frame for clarity of illustration,

FIG. 2 is a similar view of the bolster only with parts thereof broken away for greater clarity of illustration,

FIG. 3 is an elevational section taken on line 3-3 of FIG. 1, I 7

FIG. 4 is'a view similarto that of FIG. 3, but showing the car body supported by the truck frame in an inclined attitude, as when traversing a, curve,

FIG. 5 is a schematic diagram of the control circuit for the automatically-operated bolster Y contering devices of the embodiment, I

FIG. 6 is a schematic diagram of a control system for controlling the tiltingof thecar bodies of a passenger train relative to their respective trucks as the .train moves around a curve, I FIG.:7 is a'perspective exploded view, similar to FIG. I, of a second embodiment,

. FIG. 8 is a perspective exploded view of av minor detail of the second embodiment, and

FIG. 9 is an elevational section taken on line 9-9 of FIG. 7, and a FIG. 10 is a view similar to that of FIG. 9, but showing' thecar body supported by the truck frame in an inclined attitude, as when traversing a curve.

Similar parts are given the same reference number in all the Figures of the drawings.

DESCJRIPTION or THE PREFERRED EMBODIMENTS Referring now -to FIGS. 1' to 4, the particular preferred embodiment comprises a four-wheel, highspeed passenger truck, having a frame which is a unitary steel casting to providemaximum rigidity. The frame teristic of a highly damped spring and are able to accommodate a substantial amount of movement along their longitudinal axis, while permitting relatively high shear displacement of their end plates, the shear characteristic being controllable by control of the compression along the said axis. The compression axes of the two units 19 supporting each journal 18 are inclined towards each other to intersect at or close to the normalloaded position of the rolling axis of the axle.

The car body that is to be mounted on the truck is indicated diagrammatically herein in FIGS. 3 and 4. as a flat floor member 20, having two downwardly extending bracket members 21 fastened to the underside thereof on either side adjacent each truck. Bolster frame means for mounting the body on the truck frame comprise lower and upper bolster members 22 and 23 respectively, the lower bolster member 22 being supported by the side frames andpivotally connected to the frame between-the transoms I2 and 13, while the upper bolster member 23 is supported by the lower bolster member and in turn supports the vehicle body comprises two parallel side frame members 10 and 11,

which have their center portions( l0a and 11a respectively) depressed to the greatest possible extent, these members being connected to one another intermediate their ends by two longitudinally-spaced transoms 12 and 13. The truck runs on two similar wheel and axle assembles, each constituted by a respective axle l4 and pair of wheels 15. They truck is of course provided with conventional brakes, but the specificdetails of the construction and arrangement thereof will be apparent to those skilled in the art, and are not further described herein since they form no part of the present invention. A truck in accordance with the present invention may also be a motorized unit, in which case each axle will, for example, be driven by a respective electric motor and gear unit not illustrated) mounted on the frame and operatively connected to the respective axle.

Each axle 14 is rotatably mounted in the frame by a respective pair of journals 18, each of which in this particular embodiment is mounted and guided for the necessary generally vertical movement by two resilient suspension units 19. These suspension units are of the kind comprising a plurality of flat layers of a suitable 7 rubber, or a suitable rubber-like material, interleaved with flat metal plates, and provided with metal end plates by which the unit is connected respectively to the journal and the adjacent side frames. Such units operate incompression and have a'longitudinal com pression axis generally perpendicular to the plane of the said flat plates; they inherently have the charac- The means supporting the'lower bolster member 22 on the truck frame comprise four resilient suspension units 24, disposed at the four corners of a rectangle with their longitudinal compression axes generally vertical, spigots such as 25 on the lower bolster fitting into the top plate of the respective unit 24. Each suspension unit 24 is mounted between the depressed portion of the respective side frame and an upwardly curved portion of the bolster member, the arrangement permitting the use of relatively long units, while maintaining the lower bolster as low as possible in the truck in order to maintain the center of gravity of the whole truck as low as possible. The center portion'of the lower bolster is depressed as much as possible, and is provided with a downwardly extending spigot 26 that is freely rotatable without play in an aperture 27 in a pivot member 28.

The pivot member 28 is mounted between thetwo transoms 12 and 13 by two opposed longitudinallyspaced resilient suspension units 29, and also by motor 'means constituted by two opposed motor units to be surface of the respective transom and a corresponding flat surface of the pivot member 28, with the longitudinal compression axes thereof coincident and extending longitudinally of the truck, while each unit 30 extends between a flat surface of the pivot member and the adjacent end of a piston 31 of a respective motor unit 32 mounted inside the respective depressed central frame portion.

The upper bolster member 23 has the general form of an open frame, and in this embodiment comprises two parallel transverse members 33'con'nected' rigidly together by two end members 34 and a central member 35. The two end members 34 carry respective massive laterally spaced air springs 36, mounted with their comrespective openings in the upper bolster member, so as to reduce the overall height of the composite bolster as much as possible.

Each end of the upper member 23 is connected to the respective end member 34 of the lower member 22 by an articulated linkage comprising a generally Y- shaped link member 37, which is operative as a bellcrank lever and is pivoted to the member 22 about its crank pivot axis by a pivot rod 38. The end of one crank arm of the link member 37 is connected by a pivot rod 39 to the adjacent ends of two spaced parallel links 40, the other ends of the links 40 being connected by a pivot rod 41 to the member 34. The ends of the other crankarms of the Y link members 37 are connected by pivot rods 42 to the respective ends of a connecting link 43, which extends through apertures 44 provided in the member 22, the link 43 being bowed upwards to clear the depressed central portion of the member 22 over its full range of movement.

The articulated linkage is completed by means of a depending link 45 fixed rigidly at its upper end to the central member 35 and pivoted at its lower end by a rod 46 to one end of a short transverse link 47 that is disposed generally parallel to the connecting link 43 and is accommodated in a recess therein. The other end of the transverse link 47 is connected to the link 43 by a pivot rod 48.

The required rolling or tilting motion of the two bolster parts relative to one another is produced under the control of mechanism to be described in detail below, this mechanism controlling the operation of motor means comprising two double acting hydraulic units 50, which are disposed one on each side of the bolster. Each unit 50 comprises a cylinder member 51 pivotally connected at 52 to the lower bolster member 22 and a piston member 53 pivotally connected at 54 to the upper member 23. It will be apparent that of course the connection of the units 50 can be reversed. Diagonally extending links 55 (FIG. 1) are connected by spherical rubber bushings to the lower bolster 22 and to brackets 56 fastened to the car floor approximately in the center thereof, so that they will not foul the truck side frames as the car body tilts relative thereto. Laterally extending links 57 (FIGS. 3 and 4) are connected by similar bushings to the upper bolster member and the brackets 21 of the car floor. These links 55 and 57 ensure that there can be no substantial transverse and/or longitudinal motion between the bolster and the car body, and the springs 36 are required to accommodate only vertical displacement and to provide only vertical springing.

The action of the connecting linkage can be seen by a comparison of FIGS. 3 and 4, which show the upper bolster member respectively in its horizontal position and in one of its extreme tilted positions. It is important to note that one action of the linkage is to keep the roll center 58 approximately stationary in the position illustrated during the bolster tilting, avoiding the large lateral motions that would be encountered for example with a suspension comprising two spaced single links. The tilting action illustrated in FIG. 4 is produced by an increase in length of the motor units 50, forcing the upper bolster member 23 to the left (as seen in the FIGURE) relative to the lower member 22. This movement of the upper member 23 causes a corresponding clockwise movement of the links 37 about the rods 38 via the connection constituted by the end members 34 and the links 40. This lateral movement of bolster member 23 causes a corresponding lateral movement of connecting link 43, via the links 45 and 47, that applies an additional clockwise rotation to the bell-crank links 37. In the absence of the links 43, 45 and 47, and their described action on the links 37, the lateral displacement of the upper bolster member would cause it to tilt about a laterally moving effective axis disposed approximately midway between the rods 38, and at the same level as the axes of these rods (i.e. below the level of the floor The effect of these additional links is therefore to raise the height of the tilt axis 58, and by careful choice of the lengths of the individual links of the articulated linkage it can be located in the desired position.

In this particular embodiment the immediately ad- 20 jacent ends of the two bolster members have the lower bolster member end above the respective upper bolster member end, so that the upper bolster member is suspended by the articulated linkage from the lower bolster member. It is also contemplated that the two bolster members may be suspended from one another by some other means, the connecting linkage ensuring that the required relative movement takes place between them upon operation of the motor units 50.

In a passenger vehicle the preferred height of the axis 58 above the car floor is such that it is located approximately at the level of an elbow of the average seated passenger. The actual determination of the lengths of the links to achieve this result for a particular truck construction can be effected by one of the methods known to those skilled in the art, such as a graphical method.

Referring especially to FIG. 5, each of the motor units 32 is supplied with an operating liquid under pressure, usually a suitable oil. This liquid is drawn from a reservoir 60 by a pump 61 and supplied thereby to a pressure reservoir 62, the pump being controlled in a known manner by means which are not shown to maintain the liquid in the reservoir 62 between predetermined pressure limits. Liquid from the reservoir is fed via pipes 63 to two servo valves 64, which are controlled via pipes 65 from a hydraulic slave pilot transducer 66. The transducer 66 is in turn controlled electrically by a master transducer device, indicated herein as box 67, and to be described in more detail below. The servo valves 64 feed liquid via respective pipes 68 and air-containing reservoirs 69 to their respective motor units 32. While the truck is running straight the servo valves 64 maintain substantially equal high pressures in their motor units 32, centering the member 27, the excess oil returning to the reservoir 60 via pipes 70. The usual random track forces applied to the member 27 are absorbed by the reservoirs 69, the air in these reservoirs causing them to act as air springs.

As the vehicle traverses a curve corresponding large lateral centrifugal forces are applied to the lower bolster member, and thence to the pivot pin 26 and pivot member 27, so that the latter is urged to move off center. The device 67 feeds a corresponding control signal to the slave transducer 66 that in turn operates one or both of the servo valves 64 to effectively increase the pressure applied to one motor unit and decrease the pressure applied to the other motor unit, so that a corresponding force is applied to the member 27 by the units opposing the said centrifugal forces and urging the member 27 to return to its central position.

Such a control can be arranged to maintain the member 27 substantially central at all times, with the result that the shear forces applied to the suspension units 24 and 29 are very considerably reduced, so that more resilient units can be used than if these units sustained the effect of these lateral forces. Such more resilient units of course result in a softer and quieter suspension. I

In an alternative arrangement the centering of the member 27 is controlled by a movement detector member 26a mounted on the pivot member 27 and connected by a link 27a to one of the side frames. The detector member canoperate as described above for transducer 67, or may be mechanically connected to a servo valve, such as the valve 64, that is operative under control of the detector member to supply additional oil under pressure to the appropriate motor unit cylinder 32 until the pivot block has been moved back to its center position. Such a centering system operates completely automatically under control of the detector member and independently of the tilting control system. In this embodiment the oil supplied from the pump 61 and reservoir 62 is also fed to the tilting motor means 50 via connecting pipes 71 and a servo valve 72.

Since the links 55 and 57 between the upper bolster member 23 and the car body 20 prevent relative lateral and rotational motions thereof only relative vertical motion need be accommodatedby the main secondary suspension air springs 36. Such springs do not therefore have to resist and /or accommodate the relatively large lateral translation motions that would otherwise be applied to them by a fast moving train. The connection between the upper and lower bolster members, namely the articulated linkage and the operator units 50, only permit relative lateral motion thereof under the control of the units 50, which is in effect a rotationalmotion about the center 58. The weight of the car body and of the bolster is supported from the truck frame by the units 24 which are designed principally to accommodate the pivoting of the vehicle body on the truck as it traverses a curve. The wheel primary suspension units 19 permit vertical translation of the axle l and a limited lateral translation of the wheels relative to the frame, such as to accommodate the usual irregularities in the track.

It will be seen therefore that the various required springing and mounting functions are separated out into three distinct groups, thereby assisting in permitting conventional components to be used. The first group comprises the upper bolster member 23 and the associated air springs 36 which provide vertical secondary springing with no lateral motion. The second group comprises the mounting of the upper bolster member to the lower bolster member, whereby the two members function as a single unit between the frame and the car body for mounting the latter, but are moved relative to one another to provide the lateral tilting of the car body. The third group comprises the special pivot suspension which freely permits the pivoting motion of the bolster relative to the truck frame, accommodates lateral displacements of the bolster relative to the truck frame and permits the bolster structure to remain centered despite high lateral centrifugal forces generated by deficiencies in the track super-elevation.

It will therefore be apparent to those skilled in the art that all of the parts of the suspension are of relatively conventional construction and can readily be manufactured and services using conventional existing equipment, shop skills and personnel.

Referring now especially to FIG. 6, there is schematically illustrated therein a control system for operation of the tilting motor units 50 of an entire train comprising a leading car or locomotive 74 and cars 75 running on tracks 76. A first gyroscopic or inertial device 77 is mounted on the forward truck of the locomotive and detects the rate of deviation of the truck frame from the horizontal. A second gyroscopic or inertial device 78 is mounted on the locomotive body and determines a rate of change of direction thereof from a straight line path, the device effectively being used to compute the radius of the curve around which the locomotive is passing. The outputs of these two devices, together with that of a speedometer 79, if required, are fed to a control device 73 which produces an output corresponding to the amount of lean or tilting'required for the car body to ensure that the lateral forces which will be applied to the passengers are below the desired 1 level. This amount depends principally upon the radius of curvature of the track, the amount of banking or super-elevation already provided by the track at the curve, and the speed of the train. This output is fed to the servo 72 which in turn produces the required operation of the motor units 50. The output of the device 73 can also be fed to the device 67 for control of the motor units 32 as described above. Each car of the train is thereby self contained and controls its own tilting independently of the other cars.

In another arrangement the device 73 of the lead car or locomotive 74 may feed a signal to the device 73 of the immediately succeeding car, via a.connection 80, so that the inevitable delay in operation of the motor units 50 and 32 can be compensated, at least to some extent. In another systemthe device 73 of the lead car or locomotive feeds a signal to a computing and timing device 81 via a lead 82, the device 81 being connected by a multiple lead 83 to the device 73 of the succeeding cars and supplying the appropriate signal at the appropriate time to each device 73, so that it operates the servo valves 72 and the motor units 50 associated with that car for the car body to achieve the desired tilting relative to its trucks as the car reaches the position occupied by the leading car or locomotive 74 at the time that the corresponding measurement was made. Thus the signal will initially be applied immediately to the lead car to cause its body to lean, while the signal fed to the servo of the first car will be delayed an appropriate amount, depending on the speed of travel of the train as determined by the speedometer 79, and so on, so that all of the cars pass round the curve with the appropriate amount of tilting at all times. In the case that a locomotive is employed it may be preferred that its body does not lean.

In the embodiment illustrated by FIGS. 7 to 10 the link means permitting the desired tilting of the car body about the longitudinal tilting axis, comprising articulated linkage 37 to 45, mount the lower bolster member 22 to the truck frame, each of the pivot rods 38 having its ends mounted in a respective pair of parallel transverse projections 86 upstanding from the truck frame. The whole bolster therefore moves in the required rolling or tilting motion relative to the truck frame under the control of the motor units 50, which are connected between the frame and the lower bolster member 22.

The upper and lower bolster members are supported for pivoting movement relative to one another, to permit corresponding pivoting movement of the truck relative to the car body, by the four resilient suspension units 24, the pivot member 28 extending upwardly from the lower bolster member to engage the two units 29. Resilient bumpers 87 are provided to cushion the small transverse movements permitted to the member 28 relative to the upper bolster member.

The means mounting the car body 20 to the bolster are the same as in the embodiment of FIGS. 1 to 4, the links 55 and 57 preventing relative lateral and rotational motions, so that the springs 36 need only accomodate relative vertical motions. Additional damping units 88 are provided connected between the upper bolster member and the car floor. The wheel primary suspension units 19 permit vertical translation of their respective axles etc., as with the first-described embodiment. The weight of the car body and of the upper bolster member is supported from the truck frame and the lower bolster member by the units 24, additional damping members 88 being connected between the bolster members. The articulated link connection between the lower bolster member and the truck frame provides the desired relative lateral motion under the control of the units 50. As with the first-described embodiment therefore the various required springing and mounting functions are separated out into three distinct groups, so that virtually the same conventional components may be used.

The embodiment of FIGS. 7 to 10 is particularly suitable for application to passenger cars, and does not require an automatic pivot centering arrangement since the lateral motion of the two bolster members permitted by the members 24 is much less than that permitted by the articulated linkage; the embodiment of FIGS. 1 to 4 with such an automatic centering arrangement is more particularly applicable to locomotives with motorized trucks. A tilting control system that is particularly applicable to the embodiment of FIGS. 4 to 7 involves the use of an accelerometer 89 mounted by a bracket 90 on the upper bolster member 23, to be located on the longitudinal center line of the car, and so that none of the transversely resilient mounting means (i.e., the link means and the units 24) are interposed between it and the car body. Ideally the accelerometer is located at the roll axis 58, but an acceptable compromise is for the device to be mounted as close as is practicable to the underside of the car floor. The accelerometer measures the transverse acceleration to which the car body is subjected as the vehicle traverses a curve, and its output is fed to a null-seeking circuit corresponding to the control device 73 of FIGS. 5 and 6, which controls the motor units 50 in the sense and to the extent necessary to produce automatically a null or minimum in the accelerometer output.

What we claim:

1. A railway truck comprising a truck frame member constituted by transversely spaced side frames and transom means extending between and connecting the said side frames; at least two wheel and axle assemblies mounted by the frame member and on which the truck runs; bolster means mounted by the frame member and adapted to support a vehicle body thereon for pivoting and tilting movement relative thereto, the said bolster means comprising an upper bolster member and a lower bolster member, spring mounting means on the upper bolster member for mounting the vehicle body for generally vertical springing movement relative thereto, pivotal mounting means connecting the lower bolster member and the frame member for pivoting movement about a generally vertical pivot axis, link connecting means pivotally connected to the upper and lower bolster members and connecting the said members for lateral, arcuate movement of the upper member relative to the lower member abut a longitudinal tilting axis of the frame member; and motor means means connected between the link-connected members and operative to produce the said lateral, arcuate movement therebetween.

2. A truck as claimed in claim 1, characterized in that the said cooperating pivotal mounting means comprise four resilient suspension units disposed in two laterally spaced pairs, each pair mounting a respective side of the lower bolster member on the truck frame, the axes of the said units being disposed generally vertical.

3. A truck as claimed in claim 1, wherein the spring means mounting the vehicle body on the upper bolster member comprise two laterally spaced air springs disposed diametrically on opposite sides of the pivot axis and interposed between the upper bolster member and the body to provide vertical springing motion of the body relative to the truck, and lateral link means connected between the upper bolster member and the body for constraining relative lateral displacement thereof.

4. A truck as claimed in claim 1, wherein the said link connecting means comprise two laterally spaced links disposed on diametrically opposite sides of the pivot axis, and interconnecting link means connected to said laterally spaced links and constraining them for corresponding pivoting movement in response to lateral movement of the said interconnecting link means.

5. A truck as claimed in claim 4, wherein each of said laterally spaced link means comprises a bell-crank shaped link pivotally connected about its crank axis to the lower bolster member and having the said interconnecting link means pivotally connected to one crank arm thereof, and a depending link pivotally connnected to the other crank arm and to the upper bolster member.

6. A truck as claimed in claim 4, wherein the lower bolster member has portions thereof extending above corresponding portions of the upper bolster member and the upper bolster member is suspended by the said laterally spaced link connecting means from the lower bolster member.

7. A truck as claimed in claim 4, and comprising subsidiary link means connecting said interconnecting link means and the upper bolster member and constraining 8. -A truck'as claimed in claim 7, characterized in.

that said subsidiary link means comprise a depending link connected to the upper bolster member, and an intervening laterally extending link member pivotally connected to the said depending link and said interconnecting link means.

9. A truck as claimed in claim 1, wherein the said cooperating pivotal mounting means comprises a pivot member mounted for lateral movement relative to the truck frame by opposed longitudinally extending resilient suspension units having their compression axes coincident and disposed longitudinally of the truck.

10. A truck as claimed in claim 9, characterized in that the said cooperating pivotal mounting means comprise four resilient suspension units disposed in two laterally spaced pairs, each pair mounting a respective side of the lower bolster member on the truck frame, the axes of the said units being disposed generally vertical.

11. A railway truck comprising a truck frame member constituted by transversely spaced side frames and transom means extending between and connecting thesaid side frames; at least two wheel axle assemblies mounted by the frame member and on which the truck runs; bolster means mounted by the frame member and adapted to support a vehicle body thereon for pivoting and tilting movement relative thereto, the said bolster means comprising an upper bolster member and a lower bolster member, spring mounting means on the upper bolster member for mounting the vehicle body for generally vertical springing movement relative thereto, pivotal mounting means connecting the upper and lower bolster members for pivoting movement about a generally vertical pivot axis, and link connecting means pivotally connected to the lower bolster member and the frame member and connecting the lower bolster member for lateral, arcuate movement relative to the frame member about a longitudinal tilting axis of the frame member; and motor means connected between the link-connected members and operative upon actuation of the motor means to produce the said lateral, arcuate movement therebetween.

12. A truck as claimed in claim 11, characterized in that the said cooperating pivotal mounting means comprise four resilient suspension units disposed in two laterally spaced pairs, each pair mounting a respective side of the respective bolster member on the other bolster member, the axes of the said units being disposed generally vertical.

13. A truck as claimed in claim 11, wherein the spring means mounting the vehicle body on the upper bolster member comprise two laterally spaced air springs disposed diametrically on opposite sides of the pivot axis and interposed between the upper bolster member and the body to provide vertical springing motion of the body relative to the truck, and lateral link means connected between the upper bolster member and the body for constraining relative lateral displacement thereof.

I 14. A truck as claimed in claim 11, wherein the said link connecting means comprise two laterally spaced links disposed on diametrically opposite sides of the pivot axis, and interconnecting link, means-connected thereof, and a depending link pivotally connected to the other crank arm and to the lower bolster member.

16. A truck as claimed in claim 14, wherein the truck frame has portions thereof extending above corresponding portions of the lower bolster member'and the lower bolster member is suspended by the said laterally spaced link connecting means from the truck frame.

17. A truck as claimed in claim 14, and comprising subsidiary link means connecting said interconnecting link means and the lower bolster member and constraining the interconnecting link means for lateral movement upon operation of the motor means.

18. A truck as claimed in claim 17, characterized in that said subsidiary link means comprise a depending link connected to the lower bolster member, and an intervening laterally extending link member pivotally connected to the said depending link and said interconnecting link means.

19. A truck as claimed in claim 1, wherein the said cooperating pivot means comprises a pivot member mounted on its respective bolster member for lateral movement relative to the truck frame by opposed longitudinally extending resilient suspension units having their compression axes coincident and disposed lon- 1 gitudinally of the truck.

20. A truck as claimed in claim 19, characterized in that the said cooperating pivotal mounting means comprise four resilient suspension units disposed in two 

1. A railway truck comprising a truck frame member constituted by transversely spaced side frames and transom means extending between and connecting the said side Frames; at least two wheel and axle assemblies mounted by the frame member and on which the truck runs; bolster means mounted by the frame member and adapted to support a vehicle body thereon for pivoting and tilting movement relative thereto, the said bolster means comprising an upper bolster member and a lower bolster member, spring mounting means on the upper bolster member for mounting the vehicle body for generally vertical springing movement relative thereto, pivotal mounting means connecting the lower bolster member and the frame member for pivoting movement about a generally vertical pivot axis, link connecting means pivotally connected to the upper and lower bolster members and connecting the said members for lateral, arcuate movement of the upper member relative to the lower member abut a longitudinal tilting axis of the frame member; and motor means means connected between the linkconnected members and operative to produce the said lateral, arcuate movement therebetween.
 2. A truck as claimed in claim 1, characterized in that the said cooperating pivotal mounting means comprise four resilient suspension units disposed in two laterally spaced pairs, each pair mounting a respective side of the lower bolster member on the truck frame, the axes of the said units being disposed generally vertical.
 3. A truck as claimed in claim 1, wherein the spring means mounting the vehicle body on the upper bolster member comprise two laterally spaced air springs disposed diametrically on opposite sides of the pivot axis and interposed between the upper bolster member and the body to provide vertical springing motion of the body relative to the truck, and lateral link means connected between the upper bolster member and the body for constraining relative lateral displacement thereof.
 4. A truck as claimed in claim 1, wherein the said link connecting means comprise two laterally spaced links disposed on diametrically opposite sides of the pivot axis, and interconnecting link means connected to said laterally spaced links and constraining them for corresponding pivoting movement in response to lateral movement of the said interconnecting link means.
 5. A truck as claimed in claim 4, wherein each of said laterally spaced link means comprises a bell-crank shaped link pivotally connected about its crank axis to the lower bolster member and having the said interconnecting link means pivotally connected to one crank arm thereof, and a depending link pivotally connnected to the other crank arm and to the upper bolster member.
 6. A truck as claimed in claim 4, wherein the lower bolster member has portions thereof extending above corresponding portions of the upper bolster member and the upper bolster member is suspended by the said laterally spaced link connecting means from the lower bolster member.
 7. A truck as claimed in claim 4, and comprising subsidiary link means connecting said interconnecting link means and the upper bolster member and constraining the interconnecting link means for lateral movement upon operation of the motor means.
 8. A truck as claimed in claim 7, characterized in that said subsidiary link means comprise a depending link connected to the upper bolster member, and an intervening laterally extending link member pivotally connected to the said depending link and said interconnecting link means.
 9. A truck as claimed in claim 1, wherein the said cooperating pivotal mounting means comprises a pivot member mounted for lateral movement relative to the truck frame by opposed longitudinally extending resilient suspension units having their compression axes coincident and disposed longitudinally of the truck.
 10. A truck as claimed in claim 9, characterized in that the said cooperating pivotal mounting means comprise four resilient suspension units disposed in two laterally spaced pairs, each pair mounting a respective side of the lower bolster member on the truck frame, the axes of the said units being disposed generally vertical.
 11. A railway truck comprising a truck frame member constituted by transversely spaced side frames and transom means extending between and connecting the said side frames; at least two wheel axle assemblies mounted by the frame member and on which the truck runs; bolster means mounted by the frame member and adapted to support a vehicle body thereon for pivoting and tilting movement relative thereto, the said bolster means comprising an upper bolster member and a lower bolster member, spring mounting means on the upper bolster member for mounting the vehicle body for generally vertical springing movement relative thereto, pivotal mounting means connecting the upper and lower bolster members for pivoting movement about a generally vertical pivot axis, and link connecting means pivotally connected to the lower bolster member and the frame member and connecting the lower bolster member for lateral, arcuate movement relative to the frame member about a longitudinal tilting axis of the frame member; and motor means connected between the link-connected members and operative upon actuation of the motor means to produce the said lateral, arcuate movement therebetween.
 12. A truck as claimed in claim 11, characterized in that the said cooperating pivotal mounting means comprise four resilient suspension units disposed in two laterally spaced pairs, each pair mounting a respective side of the respective bolster member on the other bolster member, the axes of the said units being disposed generally vertical.
 13. A truck as claimed in claim 11, wherein the spring means mounting the vehicle body on the upper bolster member comprise two laterally spaced air springs disposed diametrically on opposite sides of the pivot axis and interposed between the upper bolster member and the body to provide vertical springing motion of the body relative to the truck, and lateral link means connected between the upper bolster member and the body for constraining relative lateral displacement thereof.
 14. A truck as claimed in claim 11, wherein the said link connecting means comprise two laterally spaced links disposed on diametrically opposite sides of the pivot axis, and interconnecting link means connected to said laterally spaced links and constraining them for corresponding pivoting movement in response to lateral movement of the interconnecting link means.
 15. A truck as claimed in claim 14, wherein each of said laterally spaced link means comprises a bell-crank shaped link pivotally connected about its crank axis to the truck frame and having the said interconnecting link means pivotally connected to one crank arm thereof, and a depending link pivotally connected to the other crank arm and to the lower bolster member.
 16. A truck as claimed in claim 14, wherein the truck frame has portions thereof extending above corresponding portions of the lower bolster member and the lower bolster member is suspended by the said laterally spaced link connecting means from the truck frame.
 17. A truck as claimed in claim 14, and comprising subsidiary link means connecting said interconnecting link means and the lower bolster member and constraining the interconnecting link means for lateral movement upon operation of the motor means.
 18. A truck as claimed in claim 17, characterized in that said subsidiary link means comprise a depending link connected to the lower bolster member, and an intervening laterally extending link member pivotally connected to the said depending link and said interconnecting link means.
 19. A truck as claimed in claim 1, wherein the said cooperating pivot means comprises a pivot member mounted on its respective bolster member for lateral movement relative to the truck frame by opposed longitudinally extending resilient suspension units having their compression axes coincident and disposed longitudinally of the truck.
 20. A truck as claimed in claim 19, characterized in that the said cooperating pivotal mounting means comprise four resilient suspension units disPosed in two laterally spaced pairs, each pair mounting a respective side of the respective bolster member on the other bolster member, the axes of the said units being disposed generally vertical. 